<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Title</title>
  </head>
  <body>
    <div id="app">
      {{ list }}
      <button @click="list.push(1)">addItem</button>
    </div>
  </body>
  <script src="../dist/vue.js"></script>
  <script>
    let app = new Vue({
      el: '#app',
      data () {
        return {
          list: []
        }
      }
    })
  </script>
</html>
